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Rocks, minerals, and powdered catalysts, not considered "typical" positron annihilation spectroscopy materials were included in these studies, to find the optimal way to characterize atypical materials by the most appropriate set of parameters in a well-defined environment. The positron annihilation spectroscopies: the Doppler broadening and positron lifetime were compared with other supplementary techniques to validate, interpret, and understand the results in different materials better. It was found that although rocks are heterogeneous mineral aggregates, some positron annihilation spectroscopy values were specific for various types of rocks, potential oil deposits, and their conditions; and quite different for opals due to Ps formation there; moreover in order to characterize properly samples with small mass and density (catalytic powders), their measuring geometry, matrix effect, and set of operational parameters needed to be well-defined. [ABSTRACT FROM AUTHOR]

Domestic production of high specific activity 60 Co was halted after a target rupture in 2012 at the Advanced Test Reactor (ATR). The Isotope Program (IP) within the US Department of Energy (DOE) Office of Science tasked a multilaboratory team of researchers and managers from Oak Ridge and Idaho National Laboratories with the redesign the radioisotope capsule. The objective of this effort was to create a more robust and reliable design, compared to the pre-2012 target. The team successfully completed this task to produce the DOE-IP cobalt (Co) production capsule design. Furthermore, 66 capsules were successfully fabricated by Oak Ridge National Laboratory (ORNL) and delivered to Idaho National Laboratory (INL) for irradiation in the ATR between January 2014 and October 2016. This paper describes the efforts of the team to prepare and disposition the two initial DOE-IP Co production capsules that were processed in March 2020. These efforts include performing accurate production predictions, experimentally validating predictions with assay measurements, shipping with the Orano-furnished Battelle Energy Alliance Research Reactor shipping package, and disassembling capsules at the isotope vendor site., (Copyright © 2020. Published by Elsevier Ltd.)

The initial phase of Plutonium-238 (Pu-238) production for radioisotope thermal generation is described here in detail. Two dosimeters with/without cadmium sleeve containing Neptunium-237 (Np-237) and other neutron sensors were inserted into the low power Advanced Test Reactor Critical (ATRC) for Pu-238 production testing. The gamma-ray energy measurements from Np-238, the short-lived intermediate product, confirmed that sizable amount of Pu-238 can be produced in the full power Advanced Test Reactor (ATR). The Pu-238 production determined from the irradiation experiment was in accord with the modelling predictions. Detailed studies of the Au/Cu sensors for thermal and epithermal flux analysis and their consistency for sensors in different locations, bare and in Cd-sleeve, provided confidence in the Pu-238 production data., (Copyright © 2020 Elsevier Ltd. All rights reserved.)